Shadow Treasurer Joe Hockey has predicted that if Barack Obama loses the US election, it will be because he over-promised to voters and disappointed them.
In a breakfast address to the Sydney Institute on Wednesday, Mr Hockey said that there was a danger in offering "endless hope and blue sky".
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"During the course of this US presidential campaign, I've kept asking myself, 'If you were a first time voter for President Obama a few years ago and you had either lost your job or you were in fear of losing your job, would you really go to the effort of going out and voting again with that air of disappointment? No matter how much you had reservations about voting for ... Mitt Romney?'"
In comments that may become diplomatically uncomfortable in the event of an Obama win and a Coalition government win at the next federal election, Mr Hockey said that if Mr Obama was not returned, there was a lesson for everyone.
"It does come down to the fact that you cannot over-promise in politics anywhere, it leaves an air of disappointment."
Mr Hockey also told the breakfast audience that he had met with Republican vice-presidential candidate Paul Ryan last December, and that Mr Ryan had been "very interested in what we were doing in Australia", particularly former treasurer Peter Costello's intergenerational report.
However, Foreign Minister Bob Carr said that if Mr Obama did not win the US election, it would be because of the global financial crisis.
"It would be bitterly disappointing for all those who endorse Obama in the circumstances of his election in 2008, but it would reflect nothing other than the sluggish nature of the American economic recovery in the wake of what's summed up in the initials GFC," Senator Carr told ABC's Lateline.
Earlier former prime minister Kevin Rudd tipped Mr Obama to win a second term.
With the election currently looking too close to call, Mr Rudd predicted on Tuesday night that President Obama would edge out Mitt Romney.
In a conversation with Phillip Adams on ABC Radio National, Mr Rudd said that he had been speaking to "friends on the ground" campaigning in the swing state of Virginia.
"I know Barack reasonably well, he's a good man. I've only met Governor [Mitt] Romney once," Mr Rudd said.
"So leaving aside what you want to happen ... I think it's more probable than not that President Obama will have four more years."
Speaking about the close relationship he enjoyed with Mr Obama during his prime ministership, Mr Rudd noted that the US President was a complex leader.
"A lot of folk don't quite get him, his complexity."
Treasurer Wayne Swan said that his recent criticisms about the US Tea Party would not pose a problem for him working with a possible Romney administration.
Mr Swan said there was "pretty good dialogue" with between parties on "both sides of the aisle".
"I've worked very closely with American politicians over a long period of time," Mr Swan told Sky News.